A Review on Suspension Thermal Spray Patented Technology Evolution

Since the introduction of suspension thermal spray (STS) in 1997, the rapid evolution of this technology has resulted in a critical number of inventions justifying a comprehensive review. Today STS is one of the most important research and development topics in thermal spray. Due to the efforts of different industries, universities, and governmental institutions, STS has reached a certain maturity for implementation in different applications. STS includes any thermal spray process that is based on injection of a suspension of solid particles in a liquid carrier into the gas jet, such as suspension plasma spray, suspension high-velocity oxy-fuel, and high-velocity suspension flame spray. This review is on the state of the art of the STS technology and includes an overview of the current patent situation including the number of patents published in English language, patenting institutions and invention domains. Apparatus and methods, feedstock, and new material systems and applications were identified as the three main domains of focus for the STS inventions. The presented patents show a general perspective of the current situation and present the technology advancements in each domain. It also shows the potential of implementing this technology in new applications based on the needs of thermal spray market through further technology development.